As is well known, a Class II Division 1 type malocclusion is characterized by a mandibular retrusion and/or a maxillary protrusion where the lower molars are posterior to the upper molars and by a deep bite and severe overjet. In a Class II Division 2 malocclusion, there is a less severe mandibular retrusion and/or a maxillary protrusion, a very deep bite, a mild to moderate overjet and a lingual tipping of the upper incisors. The molars are in substantially normal relationship in a Class I malocclusion, but there is a deep bite as well as a mild overjet. Such malocclusions are often accompanied by positional irregularities and crowding of the anterior teeth. These conditions usually result in an abnormal bite, interference with efficient mastication and an unfavorable appearance. Malocclusions are generally treated between the ages of seven to fourteen while the alveolus and the bones of the jaws are highly susceptible to change.
Many orthopedic applicances have been proposed to correct these types of malocclusions. The Frankel appliance described in "Removable Orthodontic Appliances" by T. M. Graber and Bedrich Neumann published by W. B. Saunders Company, 1977 is relatively complex having two buccal shields, lip pads with connecting wires, a labial wire and two canine wire loops on the labial side, a heavy palatal wire with occlusal extension supports on the maxillary molars from the lingual side and a lingual wire bow with U loops on the lower front teeth of the mandible. The well known Bimler appliance is similar in some respects to the Frankel appliance and also has a complex arrangement of acrylic and wires to accomplish mandibular repositioning. It is generally recommended that these appliances be worn 23-24 hours a day which may cause inconvenience or discomfort to the wearer. The complex arrangement of wires is also prone to distortion through bending and breakage and may be in irritating contact with soft tissue. Both appliances are loose fitting in the mouth when closed and fall downward freely when the mouth is opened and exhibit extensive contact of acrylic against soft tissue.
The Bionator type appliance also described in the aforementioned book is a bulky acrylic structure with palatal wires and acrylic that rest on gum behind the lower anterior teeth. The device is free falling as are all functional type appliances, touches soft tissue extensively, is confining to the tongue so that it may be difficult to speak and should be worn twenty three hours a day. The aforementioned appliances are adapted to induce a patient to rest on the appliance in a forward and downward protrusive position with the lower jaw to correct a retrusive mandible. The effect is to extend the position of the lower jaw forward and downward rather than to bring the maxillary and mandibular arches into more correct and esthetic positions with respect to each other.
U.S. Pat. No. 4,382,783 issued to Farel A. Rosenberg June 18, 1982 discloses an intraoral dental appliance to correct retrusive mandibles in which two hinges with telescoping members are used to join an upper molar and a lower molar on both sides of the mouth. The point of attachment of each lower hinge is somewhat forward on the lower molar than the corresponding upper molar when the appliance is installed. As a consequence, closure of the mouth forces the lower jaw forward and a permanent change in the muscle-resting length and induces changes in the lower jaw and its joint. The appliance, however, restricts jaw movement, requires permanent attachment to both upper and lower teeth, and uses cemented bands which may disengage from the teeth thereby distorting the hinges and irritating soft tissue.
U.S. Pat. No. 4,439,149 issued to John Devincenzo Mar. 27, 1984 discloses a removable orthodontic appliance that includes upper and lower plates which contact each other along vertically oriented indexing planes. The tendency of the lower jaw to retract is opposed by the indexing planes of the upper plate which are located in the molar areas. The indexing planes of the upper plate bear against the indexing planes of the lower plate to maintain the jaw in a jutting forward position while not interfering with the opening and closing of the jaw. The Devincenzo appliance is operative, however, to deflect the mandible down and forward rather than to effect a more normal final relation between the maxillary and mandibular arches. It is used primarily to correct some Class II Division 1 malocclusions with deep bites where there is no crowding of the teeth as is the case with most functional appliances.
U.S. Pat. No. 4,671,766 issued to John J. Norton June 9, 1987 discloses an intraoral orthotic for treatment of temporomandibular joint problems which consists of two halves, one in the maxillary arch and one in the mandibular arch. Both halves have wings projecting from them which interlock upon closing of the mouth. When each half is positioned in its arch attached to the teeth and the mouth is closed, the wings on the two pieces engage in a predetermined position to allow the meniscus to be in a proper therapeutic position and to stabilize the surrounding muscles of mastication. The arrangement requires both an upper and lower half which may interfere with normal mouth functions and is adapted to manipulate the mandible downward and forward so that it can result in an extended mandible rather than a repositioning of both the maxillary and mandibular arches to a more normal relationship.
U.S. Pat. No. 4,433,956 issued to John W. Witzig Feb. 28, 1984 discloses an orthopedic corrector for correction of Class II Division 1 malocclusions which comprises an acrylic anterior segment molded to fit the lower mouth and anterior dentition and two acrylic posterior segments molded to fit the upper mouth and dentition of a patient. An expansion screw connects each posterior segment to the anterior segment for expandable movement between the anterior segment and the posterior segments. The appliance is expanded by adjusting the expansion screw in stages to maximize the utilization of corrective lower jaw movements which results from the anchoring of the orthopedic appliance in the patient's upper mouth. The Witzig appliance requires an upper section connected to the maxillary arch and a lower section connected to the mandibular arch which are likely to interfere with normal mouth functions. Wires are also needed for attachment of the components of the appliance to the teeth which wires may irritate soft tissue or bend to distort the appliance. Further, 23 to 24 hour wear may be necessary and adjustment of the device by the patient or other lay persons is relied on for effective therapy. The appliance also tends to irritate gums and tip the lower front teeth forward. None of the aforementioned appliances is adapted to correct moderate to severe crowding of the lower anterior teeth and all are designed to be loose fitting.
The article "Bone Remodeling, A New Orthodontic Approach for Interceptive and Total Mixed Dentition Therapy" by Leon Kussick appearing in the ASDC Journal of Dentistry for Children, January-February, 1978 discloses an orthopedic appliance comprising a single acrylic broad palatal plate removably attached to the upper teeth which may require support by a wire assembly. The broad one piece descending acrylic plate extends from the maxillary arch to define an inclined plane angled to contact the lingual edges of lower anterior teeth so that the mandible can be moved forward and upward while the maxillary alveolar arch is retracted. The corrective action is controllable and affects both the maxillary and mandibular arches but the appliance is bulky, may require wires in contact with soft tissue of the maxillary arch and successful use requires individual design, laboratory construction and considerable adjustment of the appliance for each patient by a highly skilled and specially trained dentist or orthodontist. It is an object of the invention to provide an improved oral appliance to relocate the maxillary and mandibular arches that is adapted to correct malocclusions for a large category of patients with more accurate jaw positioning control and without requiring highly specialized orthodontic skills for successful use.